La Fonda on Main, dating from 1932, claims to be the oldest Mexican restaurant in the city. An institution of such standing could rest on its laurels, but current owners Cappy and Suzy Lawton are not ones to let laurels lie. The place looks just nostalgic enough (and the courtyard, focused on a heritage oak, is perhaps the best in town), but traditional recipes have been tweaked, new ones added. Much of it works.

What doesn’t come off as well are classic plates such as the enchiladas verdes available anywhere in town. What does work remarkably well are dishes that suggest tradition, then abandon it. A cornmeal coated chile poblano stuffed with gussied up cheese and bedded on a spunky avocado-poblano sauce, all atop white rice studded with corn, is a marvel of reinvention—light yet bright in flavor. The same goes for the enchiladas de nopal, stewed cactus paddles in a brilliant red tortilla topped with a sprightly tomato sauce. The ensalada de nopalitos is equally fresh and appealing.

A tradition of long standing, “Steve’s Margarita,” billed as “tart,” is really more purely puckery, however, with a recent rendition tasting of freshly squeezed but old limes. Top shelf renditions err in the opposite direction.